Please help on tonearm upgrade for an Avid Volvere

Hi - I currently own a modified Rega RB300 arm and willing to go to the next step for another arm - plese check my system below.

The Volvere has armboards for an SME and Rega-like arms - but there are many nice options out there from Moerch to Hadcock to Graham - but not sure if that decision will get me into a nightmare of drilling and the like.

Thanks for your feedback

Fernando